Opened 17 months ago

Closed 9 months ago

Last modified 3 months ago

#18193 closed defect (fixed)

Opacity of TMS layer not applied in loading stage

Reported by: stoecker Owned by: team
Priority: normal Milestone: 20.06
Component: Core imagery Version:
Keywords: tms opacity Cc: wiktorn


I tested an TMS layer with opacity of 60% and when you zoom in and out it always happens, that some tiles are displayed with 100% and only later switch to 60%. I'd assume that happens together with loading/caching.

The visual effect is a ugly.

OTOH There are also situations where it does not happen. Maybe when loading tiles from cache?

The Layer should always honor this setting and not display tiles without correct opacity.

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Change History (12)

comment:1 Changed 17 months ago by Don-vip

Keywords: tms opacity added

comment:2 Changed 17 months ago by Don-vip

Cc: wiktorn added

comment:3 Changed 17 months ago by Don-vip

I tried to take a look and didn't understand why this problem occurs. @Wiktor do you have any clue?

comment:4 Changed 15 months ago by stoecker

I'd really appreciate if someone could have a look. That effect is very disturbing in a project where I use josm.

comment:5 Changed 15 months ago by stoecker

There is also a probably related effect that for first display newly displayed tiles are a bit shifted and jump later into correct position.

comment:6 Changed 9 months ago by stoecker

A better way to reproduce:

1) In trunk/src/org/openstreetmap/josm/data/cache/ add in line 365 before cacheData = createCacheEntry(raw) a try{Thread.sleep(5000);}catch(Exception e){}. This delays tile loading.
2) Now clear tile cache with rm.
3) start josm with a saved session displaying TMS and let it load.
4) move the screen, so that at least a new full tile is visible.

You'll see a new tile which has no opacity and is made of data from lower zoom levels. As soon as the 5 seconds are over it get's replaced with the correct level and opacity.

Thought I have still no idea why the lower stretched zoomlevels don't have some opacity. As far as I see they use the same drawing functions.

comment:7 Changed 9 months ago by stoecker

It's a bit clearer now. The higher zoom levels have lighter colors, that's why it looks different.

I'm thinking maybe the display of rescaled images can be delayed a bit (i.e. 200ms), so that it happens less often.

comment:8 Changed 9 months ago by stoecker

No. That causes dark instead of light disturbing.

Last edited 9 months ago by stoecker (previous) (diff)

comment:9 Changed 9 months ago by stoecker

Resolution: fixed
Status: newclosed

In 16669/josm:

fix #18193 - reduce flickering when paning map by loading a little bit more tiles than strictly necessary

comment:10 Changed 9 months ago by stoecker

Milestone: 20.06

comment:11 Changed 9 months ago by stoecker

In 16670/josm:

fix #18193 - typo

comment:12 Changed 3 months ago by GerdP

see #20207 for a possible regression

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